Question

What happens when the gas obtained by heating oxalic acid and concentrated H2SO4 is passed through finely divided Ni

Answer 1

Answer

The conc H2SO4 will remove the elements of water from the oxalic acid and CO and CO2 will go through the NaOH. The CO is not soluble but the CO2 with form Na2CO3 sodium carbonate. You might end up with some sulphur oxides too at 100C

Explanation

At first you need to know what happens when the first 2 products are heated, only then you can know what gasses pass trough the NaOH solution.

And that is: The weak and hydrated oxalic acid gets dehydrated& decomposed:

COOH)2. 2H2O + conc. H2SO4 + heat→ CO(gas) + CO2(gas) + [H2SO4.3H2O]

then these gasses pass trough the NaOH solution:

Co pass-trough since it is not absorbed or reacting with the hydroxide,

,but CO2 gets absorbed & reacts & becomes Na2CO3.

Answer 2

Answer:

When oxalic acid is heated in the presence of concentrated sulphuric acid, oxalic acid dehydrates or in other words, it loses its water molecules.

(COOH)_2.2H_2O + conc. H_2SO_4 + heat \rightarrow CO + CO_2 + [H_2SO_4.H_2O](COOH)

2

.2H

2

O+conc.H

2

SO

4

+heat→CO+CO

2

+[H

2

SO

4

.H

2

O]

The gases so obtained are CO and CO_2CO

2

. When the gases CO and CO2 are passed through caustic soda which is NaOH, CO being soluble, passes through and does not get absorbed and react with NaOH. CO_2CO

2

on the other hand, is not soluble and gets absorbed and reacts with NaOH to form sodium carbonate (Na_2CO_3)(Na

2

CO

3

) .